Stirling A. Colgate U.S. Pat. No. 3,616,855 describes a method of creating a region of overpressure in an underground formation by pumping a settable fluid at high pressure into the formation at the point where the overpressure is desired. The fluid fractures the rock if the pressure is great enough and fills the crack. A period of static hold allows the fluid to set to a stronger solid. The normal stress in the fracture is increased because of the added volume. A subsequent fracture may or may not reopen the original fracture. If it reopens the original one, then the new added volume will further increase the normal stress and make the subsequent fracture more difficult until after some cumulative increment of stress, the fluid finds and fractures a new direction until it too has increased in stress to where either a still different direction is fractured, or the original one is fractured again. In this fashion, the fractures find the weakest point or direction; then the injected fluid increments the stress and thus converts the weak point into a strong one. This stochastic process will find and fill fractures in all directions from the injection point. The weakest direction is turned into the strongest, and a new weakest one is found. A volcano mountain is formed in the same fashion where each lava flow that breaks out the sides turns the last weak point into a stronger point by locking in the stress created by the fracture, flow and solidification of the lava.